PS1 (Ext) - 4 - 4bb
- What does this GSE mean?
Students will be able to construct chemical formulas to represent compounds and determine the products formed by interactions of the compounds. They will be able to describe the types of compounds formed and describe the various properties associated with these products.

- What subtopics do students need to address to understand this GSE?
  • conservation of mass
  • conservation of charge
  • reactants vs. products
  • properties of compounds
  • balancing chemical equations
  • predicting products
- What ideas to students need to understand before they can address the topics described above?
  • difference between atoms and molecules
  • physical vs. chemical changes
  • chemical vs. physical properties
  • periodic table and trends
  • metals vs nonmetals
  • bonding (ionic, covalent, metallic)
  • chemical formulas (ionic, molecular)
- What misconceptions are students likely to have about these topics?
  • Absence of conservation of particles during a chemical change
  • Frequent disregard for particle conservation and orderliness when describing physical changes
  • Failure to perceive that individual substances and properties correspond to a certain type of particle. Formation of a new substance with new properties is seen as simply happening rather than as a result of particle rearrangement
  • After chemical change, the original substances are perceived as remaining even though they are altered
  • Size of atoms greatly overestimated: atoms can be seen with a microscope, water molecules are heavy enough to be weighed individually in a high school lab
  • The original substance vanishes "completely and forever" in a chemical reaction
  • Freezing and boiling are examples of chemical reactions
  • Energy is used up in chemical reactions
  • Energy is created in chemical reactions